diff options
authorIan Abbott <>2019-06-26 14:17:39 +0100
committerGreg Kroah-Hartman <>2019-07-14 08:11:20 +0200
commitc04c751bef8784347ccafeab01e109354240164b (patch)
parent4e49c6c91c18330409bd5181ccf73c6382e72c0b (diff)
staging: comedi: amplc_pci230: fix null pointer deref on interrupt
commit 7379e6baeddf580d01feca650ec1ad508b6ea8ee upstream. The interrupt handler `pci230_interrupt()` causes a null pointer dereference for a PCI260 card. There is no analog output subdevice for a PCI260. The `dev->write_subdev` subdevice pointer and therefore the `s_ao` subdevice pointer variable will be `NULL` for a PCI260. The following call near the end of the interrupt handler results in the null pointer dereference for a PCI260: comedi_handle_events(dev, s_ao); Fix it by only calling the above function if `s_ao` is valid. Note that the other uses of `s_ao` in the calls `pci230_handle_ao_nofifo(dev, s_ao);` and `pci230_handle_ao_fifo(dev, s_ao);` will never be reached for a PCI260, so they are safe. Fixes: 39064f23284c ("staging: comedi: amplc_pci230: use comedi_handle_events()") Cc: <> # v3.19+ Signed-off-by: Ian Abbott <> Signed-off-by: Greg Kroah-Hartman <>
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/staging/comedi/drivers/amplc_pci230.c b/drivers/staging/comedi/drivers/amplc_pci230.c
index 08ffe26c5d43..0f16e85911f2 100644
--- a/drivers/staging/comedi/drivers/amplc_pci230.c
+++ b/drivers/staging/comedi/drivers/amplc_pci230.c
@@ -2330,7 +2330,8 @@ static irqreturn_t pci230_interrupt(int irq, void *d)
devpriv->intr_running = false;
spin_unlock_irqrestore(&devpriv->isr_spinlock, irqflags);
- comedi_handle_events(dev, s_ao);
+ if (s_ao)
+ comedi_handle_events(dev, s_ao);
comedi_handle_events(dev, s_ai);